The Australian Work Exposures Study (AWES):
Lead and lead compounds

November 2014

The views in this report should not be taken to represent the views of Safe Work Australia unless otherwise expressly stated.

This report was prepared by Dr Tim Driscoll (MBBS BSc (Med) MOHS PhD FAFOEM FAFPHM). Dr Driscoll is an independent consultant in epidemiology, occupational health and public health, and a specialist in occupational medicine and public health medicine, and a Fellow of the Australasian Faculties of Occupational and Environmental Medicine and Public Health Medicine.

Acknowledgements

The author would like to thank Dr Renee Carey for supply of AWES data and background information on the study methodology; Dr Susan Peters and Professor Lin Fritschi for clarification of data issues; and staff at Safe Work Australia for their assistance in preparing this report. The AWES study was funded by the National Health and Medical Research Council (NHMRC grant number 1003563) and the Cancer Council Western Australia and was designed and managed by Professor Lin Fritschi, Associate Professor Deborah Glass, Dr Geza Benke, Professor Tim Driscoll, and Associate Professor Alison Reid.

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The information provided in this document can only assist you in the most general way. This document does not replace any statutory requirements under any relevant state and territory legislation. Safe Work Australia is not liable for any loss resulting from any action taken or reliance made by you on the information or material contained on this document. Before relying on the material, users should carefully make their own assessment as to its accuracy, currency, completeness and relevance for their purposes, and should obtain any appropriate professional advice relevant to their particular circumstances. The views in this report should not be taken to represent the views of Safe Work Australia unless otherwise expressly stated.

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Driscoll, T. R. (2014). The Australian Work Exposures Study (AWES):Lead and Lead compounds. Canberra: Safe Work Australia.

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PREFACE

The Australian Work Health and Safety Strategy 2012-2022 (the Strategy) describes work-related cancer as a priority disorder and understanding current hazardous exposures and the effectiveness of controls as a research priority. The Australian Work Exposures Study (AWES) was a national survey that investigated work-related exposures among Australian workers to 38 agents classified by the International Agency for Research on Cancer (IARC) as known or suspected carcinogens.

Some forms of lead areconsidered to be probable carcinogensand the work described in this report uses AWES data to:

  • estimatethe prevalence of work-related exposure to lead during relatively common workplace activities
  • identify the main circumstances of those exposures, and
  • identify the use of workplace control measures designed to decrease those exposures.

This report describes those exposures that occur when typical work activities are carried out by Australian workers—it does not specifically focus on high risk lead work or ‘lead’ industries.

KEY MESSAGES

  • Approximately 6.1% of workers who participated in the Australian Work Exposures Study (AWES) were probably exposed to lead when performing common tasks like soldering, preparing surfaces for painting, or machining metal at work.
  • The health risks posed by exposures to lead should be well understood, particularly by those undertaking work which falls within the scope of lead-specific regulations. Model Codes of Practice and work health and safety guides identify common tasks where lead exposure is a potential hazard and provide advice on preventing exposures using the hierarchy of controls.
  • However, when information on the use of controls was provided byAWES respondents, many reported:
  • only using respiratory protective equipment (RPE), or
  • not using any controls to prevent exposures.
  • As a result, many of these workers were assessed as having high or medium task-based exposures to lead. While most of these workers will not develop cancer as a result of work-related exposures to lead, they are at greater risk.
  • Awareness-raising and education efforts are required to increase the use of well-known and readily available controls to prevent exposures like using lead-free alternatives,soldering or welding booths, area ventilation, or fitting dust collectors to power tools in Australian workplaces.

TABLE OF CONTENTS

PREFACE

KEY MESSAGES

TABLE OF CONTENTS

EXECUTIVE SUMMARY

BACKGROUND

Introduction

Lead as a carcinogen

Information on exposure and control measures

Information from published literature

Information from the National Hazard Exposure Worker Surveillance (NHEWS) Survey

Australian lead regulations and guides

METHODS

The Australian Workplace Exposure Study (AWES)

Study Population

Data Collection

Exposure Assessment

Statistical Analysis

RESULTS: Information on exposure and control measures from the Australian Workplace Exposure Study

Overall results

The prevalence of exposure to lead in the Australian workforce

Circumstances of exposure

Soldering

Painting

Plumbing and handling lead flashing

Fire fighting

Radiator repair

Indoor firing range

Machining

Mining

Welding leaded steel

DISCUSSION AND INTERPRETATION OF THE STUDY FINDINGS

Exposures

Use of control measures

Gaps, strengths and weaknesses

Policy implications

Research opportunities

Exposures and health outcomes

The use of control measures

REFERENCES

LIST OF TABLES

LIST OF FIGURES

GLOSSARY

APPENDIX 1: IARC classification of carcinogens

APPENDIX 2: Job-Specific Module questions and exposure coding rules for machining metals

APPENDIX 3: Tables relevant to Figures presented in Chapter 3

EXECUTIVE SUMMARY

Background

Cancer is a priority disorder under the Australian Work Health and Safety Strategy 2012-2022 (the Strategy).Better understanding current hazardous exposures and the effectiveness of controls is a research priority under the Strategy. While some forms of lead areconsidered to be probable carcinogens there is little information about the nature of general workplace exposures to lead in Australia—regulations and data collection tend to focus on activities defined as ‘lead risk work’ where high levels of workplace exposures may occur frequently.

The Australian Work Exposures Study (AWES) is a recently-conducted nationwide survey which investigated the current prevalence of work-related exposure to 38 known or suspected carcinogens, including lead, among Australian workers. The AWES data provide an opportunity to better understand the extent and circumstance of exposure of the Australian workforce to lead.

The aim of the work described in this report was to use AWES data to estimate the prevalence of work-related exposure to lead during relatively common workplace activities, to identify the main circumstances of exposures, and to identify the use of workplace control measures designed to decrease those exposures. This report is concerned with those exposures that occur when typical work activities are carried out by Australian workers—it does not specifically focus on high risk lead work or ‘lead’ industries.

Approach

The information presented in this report comes primarily from analyses of data from the AWES project. The AWES project involved computer-assisted interviews of approximately 5000 Australian workers. OccIDEAS—an automated process of expert assessment—was used to assess the likelihood of exposures and estimate exposure levels to 38 known or suspected carcinogens based on self-reported information on work tasks and the controls being used by workers. The likelihood of exposure was assessed as none, possible or probable. Data on tasks that could result in lead exposures were extracted and examined for this report.

Prevalence estimates based on the proportion of workers in the AWES sample probably exposed to lead were applied to the Australian Bureau of Statistics 2011 Census data to provide prevalence estimates for the Australian working population. The AWES information was supplemented with limited Australian data from other sources, including from the 2008 National Hazard Exposure Worker Surveillance (NHEWS) Survey and the published literature. National level estimates were compared to prevalence estimates found in major overseas studies.

Key findings

Of the workers who completed the AWES survey:

  • 307 (6.1%) had probable exposure to lead
  • almost all workers with probable exposure were male
  • just over half of all workers with probable exposure worked in technical occupations, and
  • almost half of those with probable exposure worked in the construction industry.

The main tasks associated with probable exposures were, in decreasing order: soldering; painting old houses, ships or bridges; plumbing work; cleaning up or sifting through the remains of a fire; radiator repair work; machining metals or alloys containing lead; mining; and welding leaded steel. Some workers worked at or used indoor firing ranges. Exposure levels were assessed as being high or medium for most tasks (approximately 77%).

The main control measures workers reported using were designed to decrease the chance of exposure to lead dusts or fumes by inhalation, for example, using soldering or welding hoods, wearing respiratory protective equipment (RPE)such as face masks or half-face respirators, working outdoors or using area ventilation. However, the use of these controls was inconsistent. For example soldering was found to be the most common form of exposure to lead but the use of appropriate exposure control measures such as using respiratory protective equipment was uncommon with this activity.

If AWES estimates are applied to the Australian working population approximately 6.6% of all workers could be considered as probably exposed to lead at work. This estimate is much higher than that found in major overseas studies and is probably due primarily to differences in study methodologies in terms of the type of data collected and the approach used to estimate exposure.

Limitations

The AWES is a national population-based study providing representative exposure information on relatively common activities. Information will be lacking on most industry sub-sectors, specific occupations and specific tasks which are less common or which are undertaken by a relatively small number of people. Thus, workers undertaking tasks such as manufacturing or recycling lead-acid batteries that might result in significant lead exposures were not included in the random sample of 5023 workers—theyare a small proportion of the workforce.

Subjects included in the AWES sample were asked a series of questions about their job and the tasks involved. Some information was also obtained on the use of control measures. However, the information that could be collected on controls was somewhat limited. This was because questions asked in AWES primarily assessed if exposure could occur and then, if possible, assessed the likely level of exposure; and because there were limitations on the number of questions that could be asked while still encouraging people to participate in the project. Survey modules were based on exposures via the inhalation route. Specific questions on the provision of washing facilities or wipe-downs of dusty areas which might prevent ingestion of lead dust through hand-mouth transfers were not asked.

Exposure assessments were qualitative and refer to task or activity based exposure levels rather than to exposure standards or blood lead levels. There is therefore not necessarily any close quantitative correlation between exposures levels assessed in this study and blood-lead levels, although they would be expected to be qualitatively similar in many instances.

Policy implications

Approximately 6.6% of Australian workers are estimated to be exposed to lead when performing relatively common tasks at work. More information is required to understand the level of risk arising from these exposures in terms of cancer outcomes.

Some of the health risks posed by exposures to lead, the tasks that might result in such exposures and the methods of preventing exposure should be well understood, particularly by those undertaking work which falls within the scope of lead-specific regulations. However, the use of controls by workers in the AWES sample was generally poor. Where information on the use of controls was collected many respondents reported using RPE or reported not using any controls to prevent exposures. There is an opportunity to prevent work-related exposures to lead through efforts to increase the number of workplaces that consistently use high order controls and good work practices to eliminate or reduce these exposures. Based on the results presented in this report, some high exposures could be lowered by:

  • encouraging the use of soldering booths, area ventilation, or where this is not practicable, RPE when workers are soldering, and
  • ensuring that power sanders are fitted with dust collectors and that workers wear appropriate respiratory protective equipment when workers sand old structures prior to painting or repairing them.

Initial efforts could focus on initiatives that raise awareness or educate persons conducting a business or undertaking(PCBUs) and workers about using lead-free alternatives or using well-known and readily available controls to prevent exposures to lead.

Further research

The AWES was a population-based study and only provides exposure information on relatively common activities—it is not a dedicated study of workers employed solely in the lead industry or workers who mostly perform lead risk work. Detailed information about exposure circumstances in specific industry sectors and sub-sectors or during specific activities such as manufacturing or recycling lead-acid batteries can be obtained much more efficiently from (smaller) targeted studies.

Collecting actual measures of lead exposure when some of the tasks identified in this report are undertaken may help validate the AWES data and help better understand lead exposure levels. This information may comprise blood lead levels or air monitoring results. Blood lead levels will reflect the amount of lead absorbed through any route of exposure while air monitoring will provide information on the effectiveness of controls. Additional research examining the relationship between occupational lead exposure and cancer occurrence would also be useful.

The work presented in this report could be complemented by the collection of more widespread and more detailed information on the use of control measures when workers might be exposed to lead when undertaking relatively common activities. Further researchcould also help understand why appropriate control measures are not used. Work health and safety policy-makers and practitioners might be interested in aspects such as identifying the extent to which:

  • PCBUs and workers understand the hazards and associated potential risks
  • PCBUs and workers understand the need for various control measures and how they operate
  • higher order controls are used
  • current regulations and guidance are adequate for preventing exposures, and
  • current methods for providing risk management information and assistance to PCBUs are effective.

The Australian Work Exposures Study (AWES): Lead and Lead Compounds1

BACKGROUND

Introduction

Cancer is a priority disorder under the Australian Work Health and Safety Strategy 2012-2022(Safe Work Australia 2012c).Better understanding current hazardous exposures and the effectiveness of controls is a research priority under the Strategy. Lead is a probable carcinogen and inorganic lead compounds are classified by the International Agency for Research on Cancer (IARC) as Group 2A—Probable Human Carcinogen[1](International Agency for Research on Cancer 2006).

Lead and lead compounds, collectively referred to throughout this report as ‘lead’, are used in the manufacture of lead-acid batteries, alloys for solder and ammunition, and some plastics, protective coatings and ceramics. Past and current use of these products means that workers in a number of industries might be exposed to lead from typical work-related activities which generate lead-containing dusts or fumes. Typical work-related activities include restoration or demolition of old homes, soldering, lead casting, recycling batteries and other electronic equipment, or burning lead-stabilised plastics. While it is expected that some of these activities are undertaken in Australia there is little information about the nature of general workplace exposures. Information on the nature of exposures to lead will help inform current workplace chemicals policy development activities.

The early efforts of Australian researchers to estimate the number of workers who might be exposed to known or suspected carcinogens such as lead relied on applying overseas estimates to Australian labour force data(Australian Bureau of Statistics 2002; Fritschi & Driscoll 2006; Mathers et al. 1999; Morrell et al. 1998; Winder & Lewis 1991).The 2008 National Hazard Exposure Worker Surveillance (NHEWS) Survey attempted to collect information on chemicals used by workers and the controls provided by persons conducting a business or undertaking (PCBUs) to help address this information gap(de Crespigny 2010; MacFarlane et al. 2012). However, the data collected through the NHEWS Survey have limited utility in determining the extent of exposures to specific chemicals or the manner in which workers use controls to prevent exposures. This is because it relied on workers being aware of the specific chemical hazards with which they worked, it provided a low level of detail on controls measures, and the sampling approach meant the results werenot representative of the Australian workforce.

The recent work on the Australian Workplace Exposure Study (AWES)(Carey et al. 2014) provided the opportunity to obtain information on the prevalence of lead exposure during typical work activities at a national level. The main part of this report presents an analysis of relevant AWES data. This is followed by a consideration of the implications of the results for policy activity and future work health and safety research.